Such locking mechanisms include a housing mounted in a recess in the freight loading floor and the components of the locking mechanism are recessible into the housing below a level defined by the top surface of the loading floor when the locking mechanism is not in use. In a tie down position the components of the locking mechanism project above the floor level. A latching member and a latch operating member are journalled in the housing and biased by a tension spring connected to the latching member and the latch operating member eccentrically relative to the journals of these members.
Locking mechanisms of the type described above are supposed to tie down a piece of freight, such as a container and/or a pallet on the loading floor to maintain the freight piece in a safe position during all operational conditions of the aircraft. German Patent Publication (DE) 3,222,202 discloses a mechanism as described above, wherein the locking mechanism is equipped with so-called snap or rapid closure elements. Such locking devices can be used and locked in position in any desirable location within the loading floor of an aircraft and the size of the rapid snap closure elements will depend on the size of the freight pieces to be tied down. These locking devices can be rolled over by a piece of freight in at least one direction, even if a component of the locking mechanism projects above the loading floor level. This ability to be rolled over automatically by a piece of freight is an advantage, because it facilitates the loading operation within the freight space of the aircraft. Rolling over in an opposite direction usually requires recessing and arresting the locking mechanism below the freight floor level. In spite of the just mentioned advantage of conventional locking mechanisms, there is room for improvement, especially with regard to making such locking mechanisms more compact, particularly reducing their structural length so as to be able to make the openings in the loading floor smaller, thereby saving valuable loading space. There is also room for improvement to make these locking mechanisms less complicated in their structure.